NAME

       trace, _tracef, _traceattr, _traceattr2, _tracecchar_t, _tracecchar_t2, _tracechar, _tracechtype,
       _tracechtype2, _nc_tracebits, _tracedump, _tracemouse - curses debugging routines

SYNOPSIS

       #include <curses.h>

       void trace(const unsigned int param);

       void _tracef(const char *format, ...);

       char *_traceattr(attr_t attr);
       char *_traceattr2(int buffer, chtype ch);
       char *_tracecchar_t(const cchar_t *string);
       char *_tracecchar_t2(int buffer, const cchar_t *string);
       char *_tracechar(int ch);
       char *_tracechtype(chtype ch);
       char *_tracechtype2(int buffer, chtype ch);

       void _tracedump(const char *label, WINDOW *win);
       char *_nc_tracebits(void);
       char *_tracemouse(const MEVENT *event);

DESCRIPTION

       The trace routines are used for debugging the ncurses libraries, as well as applications  which  use  the
       ncurses  libraries.   These  functions  are  normally  available  only  with  the debugging library e.g.,
       libncurses_g.a, but may be compiled into any model (shared,  static,  profile)  by  defining  the  symbol
       TRACE.   Additionally,  some  functions  are  only available with the wide-character configuration of the
       libraries.

   Functions
       The principal parts of this interface are

       •   trace, which selectively enables different tracing features, and

       •   _tracef, which writes formatted data to the trace file.

       Calling trace with a nonzero parameter creates the file trace in the current directory  for  output.   If
       the file already exists, no tracing is done.

       The  other  functions either return a pointer to a string-area (allocated by the corresponding function),
       or return no value (such as _tracedump, which implements the screen dump for TRACE_UPDATE).   The  caller
       should  not  free  these strings, since the allocation is reused on successive calls.  To work around the
       problem of a single string-area per function, some use a buffer-number parameter, telling the library  to
       allocate additional string-areas.

   Trace Parameter
       The  trace  parameter  is  formed  by OR'ing values from the list of TRACE_xxx definitions in <curses.h>.
       These include:

       TRACE_DISABLE
            turn off tracing by passing a zero parameter.

            The library flushes the output file, but retains an open file-descriptor to the trace file  so  that
            it can resume tracing later if a nonzero parameter is passed to the trace function.

       TRACE_TIMES
            trace user and system times of updates.

       TRACE_TPUTS
            trace tputs(3X) calls.

       TRACE_UPDATE
            trace update actions, old & new screens.

       TRACE_MOVE
            trace cursor movement and scrolling.

       TRACE_CHARPUT
            trace all character outputs.

       TRACE_ORDINARY
            trace  all  update  actions.  The old and new screen contents are written to the trace file for each
            refresh.

       TRACE_CALLS
            trace all curses calls.  The parameters for each call are traced, as well as return values.

       TRACE_VIRTPUT
            trace virtual character puts, i.e., calls to addch.

       TRACE_IEVENT
            trace low-level input processing, including timeouts.

       TRACE_BITS
            trace state of TTY control bits.

       TRACE_ICALLS
            trace internal/nested calls.

       TRACE_CCALLS
            trace per-character calls.

       TRACE_DATABASE
            trace read/write of terminfo/termcap data.

       TRACE_ATTRS
            trace changes to video attributes and colors.

       TRACE_MAXIMUM
            maximum trace level, enables all of the separate trace features.

       Some tracing features are enabled whenever the trace parameter is nonzero.  Some features  overlap.   The
       specific names are used as a guideline.

   Initialization
       These  functions check the NCURSES_TRACE environment variable, to set the tracing feature as if trace was
       called:

           filter, initscr, new_prescr, newterm, nofilter, restartterm, ripoffline, setupterm, slk_init,
           tgetent, use_env, use_extended_names, use_tioctl

   Command-line Utilities
       The  command-line  utilities  such  as  tic(1) provide a verbose option which extends the set of messages
       written using the trace function.  Both of these (-v and trace)  use  the  same  variable  (_nc_tracing),
       which determines the messages which are written.

       Because  the  command-line  utilities  may  call  initialization  functions such as setupterm, tgetent or
       use_extended_names, some of their debugging output may be directed to the trace file if the NCURSES_TRACE
       environment variable is set:

       •   messages produced in the utility are written to the standard error.

       •   messages produced by the underlying library are written to trace.

       If  ncurses is built without tracing, none of the latter are produced, and fewer diagnostics are provided
       by the command-line utilities.

RETURN VALUE

       Routines which return a value are designed to be used as parameters to the _tracef routine.

PORTABILITY

       These functions are not part of the XSI interface.  Some other curses implementations are known  to  have
       similar, undocumented features, but they are not compatible with ncurses.

       A few functions are not provided when symbol versioning is used:

           _nc_tracebits, _tracedump, _tracemouse

SEE ALSO

       ncurses(3NCURSES).

                                                                                                 trace(3NCURSES)